Template-engineered metal macrocyclic complexes: Synthesis and biological activity

Three new azamacrocylic complexes of divalent transition-metal ions were synthesized by taking Co(II), Ni(II), and Cu(II) metal ions as templates. The macrocyclic ligand (1(2)Z,5(2)Z,5(4)E)-1(1),1(2),1(3),1(4),1(5),1(6),5(1),5(2),5(3),5(4),5(5),5(6)-dodecahydro-2,4,6,8-tetraaza-1 (2,4),5(4,2)-pyrimidine-3,7(1,2)-dibenzenacyclooctaphane-1(6),5(6)-dione was derived from o-phenylenediamine (OPD) and 2-thiobarbituric acid (TBA). All the complexes were fully characterized through spectroscopic techniques and elemental analyses. The structures of the macrocyclic complexes were determined by IR, UV-vis, ESI-MS, TGA, molar conductance, magnetic moment, and electron spin resonance data. On the basis of the above studies, the complexes may be formulated as [MLX2], in which L is a macrocyclic ligand and X = CH3COO-. All the macrocyclic complexes were biologically screened to evaluate their antimicrobial efficacy. DNA binding study of two representative complexes was performed by UV-vis titrations.